Mailenable, emails not sending

I have a 1and1 server hosting a couple of websites for friends and family using Mailenable for email. Currently, emails are not being sent from the server. There was a problem a week or so ago with a virus from a PC that seems to have been sending spam, this has been solved. The IP address was blacklisted by Barracuda, but this has now been removed. Even before then, there seemed to be some issues. I need someone who can look at the server, look and modify as needed any problems that there may be with Mailenable. Success criterea is that emails sent from a PC are actually sent!